Velociraptor
Velociraptor ("swift thief"Osborn, Henry F. (1924a). "Three new Theropoda, Protoceratops zone, central Mongolia". American Museum Novitates 144: 1–12. hdl:2246/3223.) is a genus of dromaeosaurid theropod dinosaur that lived in the Late Cretaceous of Mongolia. The familiar "raptor" has become one of the most well-known dinosaurs in recent years. Description Fully grown individuals of Velociraptor measured around 2 meters in length, half a meter high at the hips, and 15 kilograms in weight.Paul, Gregory S. (1988). Predatory Dinosaurs of the World. New York: Simon and Schuster. p. 464. ISBN 978-0-671-61946-6. Its skull measured up to 25 centimeters in length, and was slightly upcurved. The jaws had 26 to 28 teeth on each side, which were strongly serrated.Barsbold, Rinchen; Osmólska, Halszka (1999). "The skull of Velociraptor (Theropoda) from the Late Cretaceous of Mongolia". Acta Palaeontologica Polonica 44 (2): 189–219. Like other dromaeosaurids, Velociraptor had a large hand with three strongly curved claws on each digit. Also like its relatives, the second digit of its foot was tipped with a sickle shaped claw. In Velociraptor, this claw could measure over 6.5 centimeters in length around its outer edge. The claw was probably used to tear into and disembowel prey.Barsbold, Rinchen (1983). "Carnivorous dinosaurs from the Cretaceous of Mongolia". Transactions of the Joint Soviet-Mongolian Paleontological Expedition 19: 5–119. Feathers Other, more primitive dromaeosaurids are known to have extensive coverings of feathers on their bodies,Xu, Xing; Zhou, Zhonghe; Wang, Xiaolin; Kuang, Xuewen; Zhang, Fucheng; Du, Xiangke (2003). "Four-winged dinosaurs from China". Nature 421 (6921): 335–340. doi:10.1038/nature01342. PMID 12540892. and it was widely assumed that Velociraptor was similarly covered. This assumption was confirmed in 2007, when paleontologists reported that quill knobs had been found preserved on the forearm of a Velociraptor specimen.Turner, A.H.; Makovicky, P.J.; Norell, M.A. (2007). "Feather quill knobs in the dinosaur Velociraptor". Science 317 (5845): 1721. Bibcode:2007Sci...317.1721T. doi:10.1126/science.1145076. PMID 17885130. These structures, which are formed as bumps on the wing bones of modern birds to show where well-developed flight feathers anchor, indicate that Velociraptor had large and advanced feathers on its body. Classification Velociraptor was a dromaeosaurid, and more specifically a member of the subfamily Velociraptorinae. The contents of this subfamily are defined as "all dromaeosaurs more closely related to Velociraptor than to Dromaeosaurus." Originally, it was created solely to contain Velociraptor, but this has since been altered in several analyses.Currie, Philip J. (1995). "New information on the anatomy and relationships of Dromaeosaurus albertensis (Dinosauria: Theropoda)". Journal of Vertebrate Paleontology 15 (3): 576–591. doi:10.1080/02724634.1995.10011250. Several different dromaeosaurid genera have been classified as Velociraptor in the past, but there are currently only two valid species in the genus: V. mongoliensis (the type species) and V. osmolskae. The cladogram below is based on a 2009 analysis by Longrich and Currie:Longrich, N.R.; Currie, P.J. (2009). "A microraptorine (Dinosauria–Dromaeosauridae) from the Late Cretaceous of North America". PNAS 106 (13): 5002–7. Bibcode:2009PNAS..106.5002L. doi:10.1073/pnas.0811664106. PMC 2664043. PMID 19289829. |label2= |2= |label2= |2= }} |label2=Dromaeosaurinae |2= }} }} }} }} History During an expedition by the American Museum of Natural History to the Gobi Desert of Mongolia, the first remains of Velociraptor (a complete skull and an associated sickle claw) were discovered in 1923, at a site known as the Flaming Cliffs. The following year, museum president Henry Fairfield Osborn described the fossils and named the new genus Velociraptor, meaning "swift thief". The specific name, mongoliensis, refers to the animal's country of origin. When North American paleontologists were shut out of communist Mongolia during the Cold War, Soviet and Polish expeditions arose, in collaboration with Mongolian scientists. These expeditions recovered several new specimens of Velociraptor, the most famous of these being part of the "Fighting Dinosaurs" specimen, discovered in 1971. This remarkable fossil preserves a Velociraptor in the act of attacking a single Protoceratops.Kielan-Jaworowska, Zofia; Barsbold, Rinchen (1972). "Narrative of the Polish-Mongolian Paleontological Expeditions". Paleontologica Polonica 27: 5–13. A joint Chinese-Canadian team discovered Velociraptor fossils in northern China between 1988 and 1990.Jerzykiewicz, Tomasz; Currie, Philip J.; Eberth, David A.; Johnston, P.A.; Koster, E.H.; Zheng, J.-J. (1993). "Djadokhta Formation correlative strata in Chinese Inner Mongolia: an overview of the stratigraphy, sedimentary geology, and paleontology and comparisons with the type locality in the pre-Altai Gobi". Canadian Journal of Earth Sciences 30 (10): 2180–2195. doi:10.1139/e93-190. American paleontologists returned to Mongolia in 1990, and a joint expedition led by the American Museum of Natural History and the Mongolian Academy of Sciences discovered several well-preserved individuals of Velociraptor, among other remarkable specimens. Skull material of Velociraptor recovered in 1999 from China were found to belong to the genus, but not to the same species. As such, a second species of Velociraptor, V. osmolskae, was named by Pascal Godefroit and colleagues in 2008, after the Polish paleontologist Halszka Osmólska.Godefroit, Pascal; Currie, Philip J.; Li, Hong; Shang, Chang Yong; Dong, Zhi-ming (2008). "A new species of Velociraptor (Dinosauria: Dromaeosauridae) from the Upper Cretaceous of northern China". Journal of Vertebrate Paleontology 28 (2): 432–438. doi:10.1671/0272-4634(2008)28432:ANSOVD2.0.CO;2. Paleoecology All known examples of V. mongoliensis have been found in the Djadochta Formation (also spelled Djadokhta), in the Mongolian province Ömnögovi. This formation dates to the Campanian stage of the Late Cretaceous Period, approximately 75 million years ago. This area was an arid environment at the time that Velociraptor lived, filled with sand dunes and little water. Additional fossils, namely those of V. osmolskae, have been found in the Bayan Mandahu Formation of Inner Mongolia, China, which had a similar environment. It is likely that frequent sandstorms contributed to the preservation of fossils in these regions. V. mongoliensis shared its environment with dinosaurs such as Protoceratops and Oviraptor. Paleobiology Predatory behavior Velociraptor actively hunted prey, as evidenced by the famous "Fighting Dinosaurs" specimen. The sickle claw on the animal's foot is traditionally depicted to have been used to slash at and disembowel prey.Ostrom, John H. (1969). "Osteology of Deinonychus antirrhopus, an unusual theropod from the Lower Cretaceous of Montana". Bulletin of the Peabody Museum of Natural History 30: 1–165. In the "Fighting Dinosaurs" specimen, this claw is apparently embedded in the throat of the Protoceratops, suggesting that the Velociraptor may have been using it to pierce through vital organs which were not protected by much skin and muscle. Various tests have shown that the sickle claw might not have been able to cut through the abdominal wall of normal prey animals very easily.Carpenter, Kenneth (1998). "Evidence of predatory behavior by theropod dinosaurs". Gaia 15: 135–144. Several individuals of a related dromaeosaurid, the North American Deinonychus, have been found in association next to an individual of the ornithopod Tenontosaurus, suggesting that they may have hunted in packs.Maxwell, W. Desmond; Ostrom, John H. (1995). "Taphonomy and paleobiological implications of Tenontosaurus-Deinonychus associations". Journal of Vertebrate Paleontology 15 (4): 707–712. doi:10.1080/02724634.1995.10011256. Although Velociraptor is widely depicted to have hunted in packs, there is currently no known fossil evidence for this assumption.Norell, Mark A.; Makovicky, Peter J. (2004). "Dromaeosauridae". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka. The Dinosauria (Second ed.). Berkeley: University of California Press. pp. 196–209. ISBN 0-520-24209-2. It was suggested in 2011 that Velociraptor and relatives may have had a unique method to capture and restrain prey. Called the "raptor prey restraint" (RPR) model of predation, this hypothesis proposes that dromaeosaurids killed their prey in a manner very similar to that of modern hawks and eagles: by jumping onto the victim, pinning it under their body weight, and then gripping it tightly with their specialized claws. This hypothesis is supported by the morphology of Velociraptor and others, and it is possible that the combined adaptations developed to hunt this way may have influenced the origin of wing flapping in paravians.Fowler, D.W.; Freedman, E.A.; Scannella, J.B.; Kambic, R.E. (2011). "The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds". PLoS ONE 6 (12): e28964. Bibcode:2011PLoSO...628964F. doi:10.1371/journal.pone.0028964. PMC 3237572. PMID 22194962. Scavenging habits In 2010, paleontologist David Hone and colleagues described shed teeth of a Velociraptor found next to a tooth-marked Protoceratops bone in the Bayan Mandahu Formation. They interpreted this as scavenging behavior from a Protoceratops carcass.Hone, David; Choiniere, Jonah; Sullivan, Corwin; Xu, Xing; Pittman, Michael; Tan, Qingwei (2010). "New evidence for a trophic relationship between the dinosaurs Velociraptor and Protoceratops". Palaeogeography, Palaeoclimatology, Palaeoecology 291 (3–4): 488−492. doi:10.1016/j.palaeo.2010.03.028. Another Velociraptor specimen described in 2012 had a pterosaur bone preserved in its stomach, which was also interpreted as having been scavenged.Hone, D.; Tsuihiji, T.; Watabe, M.; Tsogtbaatr, K. (2012). "Pterosaurs as a food source for small dromaeosaurs". Palaeogeography, Palaeoclimatology, Palaeoecology. 331-332: 27. doi:10.1016/j.palaeo.2012.02.021. edit Pathology A skull of V. mongoliensis bears two parallel rows of small punctures that match the tooth patterns of a Velociraptor jaw. It is believed that the wound was inflicted by another Velociraptor during a fight. As the bone shows no sign of subsequent healing near the punctures, the wound likely killed the animal.Molnar, R. E., 2001, Theropod paleopathology: a literature survey: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p. 337-363. In popular culture Velociraptor is one of the most familiar of dinosaurs thanks to their appearance in the 1990 novel Jurassic Park and the subsequent film series. The "raptors" portrayed in the franchise were in fact more heavily modeled after Deinonychus, which was at the time of the novel classified by Gregory Paul as a species of Velociraptor, V. antirrhopus. They were depicted as being much larger than real Velociraptor, and featherless, due to the fact that feathers had not been discovered in dinosaurs until after the novel and first film.Bakker, Robert T. (1995). Raptor Red. New York: Bantam Books. p. 4. ISBN 0-553-57561-9. Although relatively unknown before Jurassic Park, Velociraptor soon after became one of the most familiar dinosaurs in popular culture, appearing in several television programs, games, and toy lines. The Toronto Raptors, an NBA basketball team, was named after Velociraptor. References Category:Animals Category:Dinosaurs Category:Carnivores Category:Theropods Category:Fossil taxa described in 1924